Work holding device for machine tool

ABSTRACT

A work holding device for a machine tool includes means for axial location on a machine tool spindle and coupling means urging the device into said coaxial location. The coupling means is operated by actuating means driven by a member extending from the machine tool. Work holding means on the device may also be driven by the same member on the machine tool.

Sept. 5, 1972 United States Patent Harman et al.

S T N m MA w SE m e my e m N u N U [54] WORK HOLDING DEVICE FOR MACHINETOOL [72] Inventors: Julius Harman, 9 Holly Walk,

9/1944 Bogart................... .279/ll4 Bagmton, Michael Eric Norman,14 Sandy Crescent, Hollycroft, 2,822,181 2/1958Sloan.........................279/l l4 Hinckley, both of EnglandAssignee: Alfred Herbert Limited, Coventry,-

Primary ExaminerG erald A. Dost Attorney-Holman & Stern England ABSTRACT[22] Filed: Oct. 15, 1970 [21] Appl. No.: 81,012

A work holding device for a machine tool includes means for axiallocation on a machine tool spindle and coupling means urging the deviceinto-said coaxial lo- Fol'elgn Appllcatlon y Data cation. The couplingmeans is operated by actuating means driven by a member extending fromthe machine tool. Work holding means on the device may GreatBritain..........50,583/69 Oct. 15, 1969 also be driven bythe samemember on the machine d m 2 mm 55 b u ,8 0g 1. 1 .7 .2." G M um 11 2 5510 Claims, 3 Drawing Figures [58] Field of Search...

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3 Sheets-Sheet 5 I NVENTOR ATTORNEYS I mw WORK HOLDING DEVICE FORMACHINE TOOL The invention relates to a work-holding device for amachine tool and has as an object to provide such a device in aconvenient form.

According to the invention a work-holding device for a machine toolcomprises a body, a locating means on the body for locating the bodycoaxially with a machine tool spindle, coupling means on the bodyadapted on actuation to engage associated means on the said spindle tourge the said locating means into close interengagement with acomplementary locating means on the spindle and actuating means mountedon the body for actuating said coupling means.

In an embodiment of the invention shown in the following drawings:

FIG. 1 shows an end view of a chuck; and

FIGS. 2 and 3 show, to a different scale, sections on the correspondinglines in FIG. 1.

A chuck has a body having one face formed with three equispaced radialgrooves 11 in which members 12 are slidable. Each member 12 is formedwith a T- slot 13 extending along its length and also with serrations 14on outwardly directed faces on either side of the slot 13. Each member12 also includes a bush 15 rotatably mounted therein and formed with atransverse arcuate slot 16 of a form later to be described.

A cam ring 17 is mounted within the body 10 for rotation about the axisthereof and includes an axially extending part 18. The faces 18a, 18b ofthe part 18 are parallel and define three arcuate portions 19 of thepart 18, each arcuate portion 19 having a center displaced from the axisof the body 10. Each arcuate portion 19 engages a respective one of theslots 16, each of which is formed with a radius substantially the sameas that of the corresponding arcuate portion 19. The periphery of thering 17 is formed with gear teeth 20. Three spur gears 21 are journalledin the body 10 and mesh with the teeth 20. Each spur gear 21 is formedwith a squaresection recess 22 adapted to receive a key means 33extending parallel to the axis of the chuck. The said key means may formpart of the associated machine tool or may be a separate item, and maybe rotated either manually or automatically.

The body 10 includes a locating means comprising a ring 23 having radialgear teeth 24 which form an interval bevel gear with a re-entrant pitchcone. The teeth 24 are adapted to engage a complementary locating meansin the form of a bevel gear fixedly mounted coaxially on the spindle 31of the associated machine tool. Rotatably engaged on the ring 23 is athreaded sleeve 25 peripherally formed with gear teeth 26 over part ofits length. The sleeve 25 is engageable with a corresponding threadedportion 32 on the associated machine tool spindle 31. Three spur gears27 are journalled in the body 10 and engage the gear teeth 26. Each gear27 is formed with a square-section recess 28 adapted to receive theaforementioned key means on the associated machine tool.

Associated with each member 12 is a jaw 29 formed on one face withserrations corresponding to the serrations 14 and also having throughholes. T-bolts 30 engageable with the T-slots 13 are mounted in the saidholes and enable the jaws to be secured in suitable radial positions onthe member 12. The chuck may thus be adapted to support workpieces ofwidely differing sizes,

notwithstanding the limited radial movement of the members 12.

In one method of use the chuck is placed in an initial axial alignmentwith the machine tool spindle and rotated until the recess 28 in one ofthe spur gears 27 is aligned with an aforementioned key means on themachine tool. The key means is then axially advanced into engagementwith the gear 27 and rotated. The sleeve 25 thus rotates and engages itscorresponding associated threaded portion on the spindle. The chuck isthereby advanced until the gear teeth of the locating means on the chuckand spindle are in close interengagement. The key means is thenwithdrawn and the chuck and spindle rotated together until the said keymeans is aligned with a recess 22 in one of the gears 21. The key meansis then used to rotate the cam ring 17 and thereby to bring the chuckjaws'into gripping engagement with a workpiece.

In an arrangement in which a key means forms part of an associatedmachine tool it may be provided that the clearance between the face ofthe chuck on to which the gears 21, 27 open and the adjacent face of themachine tool is such that when the chuck is in or near its operatingposition, gears 21, 27 can be engaged only by the said key means.

Having thus described our invention what we claim as new and desire tosecure by Letters Patent is:

l. A work holding device for machine tool, comprising: a body; aplurality of work-engaging means movably mounted on the body; firstactuating means for displacing said work engaging means in unisontowards an axis of the body; locating means on the body for locating thebody co-axially with a machine tool spindle, coupling means on the bodyadapted on actuation to engage associated means on said spindle to urgethe locating means into close interengagement with complementarylocating means on the spindle; and second actuating means on the bodyfor actuating said coupling means.

2. A device as claimed in claim 1 in which the locating means comprisesa plurality of projections on the body which engage complementaryprojections on the machine tool spindle.

3. A device as claimed in claim 2 in which the said projections compriseradially extending serrations.

4. A device as claimed in claim 3 in which the projections are in theform of bevel gear teeth.

5. A device as claimed in claim 4 in which the said teeth form aninternal bevel gear.

6. A device as claimed in claim 1 in which the coupling means comprisesa threaded portion rotatable with respect to the body and said secondactuating means is operable to rotate the coupling means.

7. A device as claimed in claim 6 in which the said second actuatingmeans is adapted to be engaged by a driving member on the machine tool.

8. A device as claimed in claim 6 in which the said threaded portion isformed on a geared ring coaxial with the body and in which the saidsecond actuating means comprises a spur gear in mesh with the ring andwith its axis in spaced parallel relationship with the axis of the body.

9. A work holding device as claimed in claim 1 wherein said firstactuating means includes a cam ring having as many cam profiles makingup the cam ring which is adapted to be rotated by the machine-tool whichmember is movable parallel to the axis of the body to selectively engageeither the first actuating means or the second actuating means.

1. A work holding device for machine tool, comprising: a body; aplurality of work-engaging means movably mounted on the body; firstactuating means for displacing said work engaging means in unisontowards an axis of the body; locating means on the body for locating thebody co-axially with a machine tool spindle, coupling means on the bodyadapted on actuation to engage associated means on said spindle to urgethe locating means into close interengagement with complementarylocating means on the spindle; and second actuating means on the bodyfor actuating said coupling means.
 2. A device as claimed in claim 1 inwhich the locating means comprises a plurality of projections on thebody which engage complementary projections on the machine tool spindle.3. A device as claimed in claim 2 in which the said projections compriseradially extending serrations.
 4. A device as claimed in claim 3 inwhich the projections are in the form of bevel gear teeth.
 5. A deviceas claimed in claim 4 in which the said teeth form an internal bevelgear.
 6. A device as claimed in claim 1 in which the coupling meanscomprises a threaded portion rotatable with respect to the body and saidsecond actuating means is operable to rotate the coupling means.
 7. Adevice as claimed in claim 6 in which the said second actuating means isadapted to be engaged by a driving member on the machine tool.
 8. Adevice as claimed in claim 6 in which the said threaded portion isformed on a geared ring coaxial with the body and in which the saidsecond actuating means comprises a spur gear in mesh with the ring andwith its axis in spaced parallel relationship with the axis of the body.9. A work holding device as claimed in claim 1 wherein said firstactuating means includes a cam ring having as many cam profiles makingup the cam ring circumference as there are work engaging means, andmeans engaging said cam profiles and constrained to move radially withrespect to the axis of the body.
 10. A work holding device as claimed inclaim 1 further comprising in combination a driving member which isadapted to be rotated by the machine-tool which member is movableparallel to the axis of the body to selectively engage either the firstactuating means or the second actuating means.